Process scale-up of cis-N-Benzyl-3-methylamino-4-methylpiperidine

The synthesis of cis-N-benzyl-3-methylamino-4-methylpiperidine via hydroboration of tetrahydropyridine followed by oxidation and reductive amination was optimized and scaled up to produce 10kg quantities of product. Three routes to were identified, and the reduction of pyridinium salt was selected as the most preferable to run on-scale. The hydroboration and oxidative workup were carefully studied to optimize throughput on that transformation, as was the reductive amination.